1. Field of the Invention
The present invention is related to a digital electric power inverter, and especially to a DC to AC power inverter particularly suitable to be used as a protection circuit module structure to control and protect the elements of the power inverter from being damaged and to be able to provide actuating power for a machine.
2. Description of the Prior Art
A conventional electric power inverter is comprised of a plurality of IC""s, when one of the IC""s is lacking, a similar IC shall be changed for it, this will make the entire performance of working influenced, and can increase difficulty of designing. The inferiority in designing thereof for overload protection is shown in FIG. 1; to satisfy the requirement for activating a heavy tool machine in the markets, huge electric power is required, if such a machine is to be actuated, several folds of monetary amount must be paid to purchase an electric power inverter with several folds of functional specification for actuating a small machine.
For example, a sand wheel needs 200W for running, while the transient power for actuating is over 1000W; therefore, in using such a machine, an electric power inverter of 1000W must be purchased. The reason is that, a conventional electric power inverter triggers a protecting loop to shut outputting in corresponding to the detecting signal from a detecting loop when the output terminal is given a heavy load, to thereby protect the interior electronic elements; this is because that conventional designing has to trigger a protecting line according to the detecting of the output state to turn off the system to protect the product. And this is the defect of the conventional design.
Therefore, the motive of the present invention is to improve the conventional electric power inverters to get rid of the above stated defects, and to provide a digital electric power inverter which sufficiently uses the control character of a CPU (a microcomputer). Thereby, the CPU turns off output in time before the output power makes the elements damaged, in order that the elements can restore their functions; a short time after restoration, the CPU turns on output again, till it once more turns off before the elements are crumbled. The process is repeated again and again to accumulate the low power outputs made in many times to get the required high actuating power for a load.
The primary object of the present invention is to provide an intermittently actuated digital electric power inverter that can gradually supply step by step the required actuating transient power output.
To achieve the above stated object, the present invention is comprised of a CPU, a PWM driving circuit, a PWM converting circuit, a rectifying circuit, an AC driving circuit, a DC/AC inverting circuit, an overload detecting circuit and an alarm circuit. The present invention is characterized by that: the entire circuitry thereof is designed to be controlled by the CPU that can accurately control these circuits to get an ability of high driving outputting.
The present invention will be apparent in its construction and other features after reading the detailed description of the preferred embodiment thereof in reference to the accompanying drawings.